Use a consistent bazel root directory (--output_user_root)

Summary:
Required to make fetching artifacts from bazel simpler.
Please see https://bazel.io/versions/master/docs/output_directories.html for details on bazel output directories.

Test Plan: Will fix tests shortly

Reviewers: kylec, naphat

Reviewed By: naphat

Subscribers: changesbot

Differential Revision: https://tails.corp.dropbox.com/D224250

changes/buildsteps/default.py

@@ -126,9 +126,8 @@ def __init__(self, commands=None, repo_path=None, path=None, env=None,
                 can be specified with "backend": "hg". Default revision is
                 "origin/master" or "default" (for hg), but an explicit revision
                 can be specified with "revision".
-            artifact_search_path: The path in which test artifacts can be
-                found in, relative to the `repo_path`. This defaults to the
-                value for `path`.
+            artifact_search_path: Absolute path in which test artifacts can be
+                found in. This defaults to the value for `path`.
         """
         if commands is None:
             raise ValueError("Missing required config: need commands")
@@ -148,7 +147,7 @@ def __init__(self, commands=None, repo_path=None, path=None, env=None,
             # default repo_path to path if none specified
             self.repo_path = path or DEFAULT_PATH
             self.path = self.repo_path
-        self.artifact_search_path = os.path.join(self.repo_path, artifact_search_path) if artifact_search_path else self.path
+        self.artifact_search_path = artifact_search_path if artifact_search_path else self.path
         self.release = release
         self.max_executors = max_executors
         self.resources = {

changes/config.py

@@ -428,7 +428,16 @@ def create_app(_read_config=True, **config):
     # Maximum memory allowed per executor (in MB)
     app.config['MAX_MEM_MB_PER_EXECUTOR'] = 16384
 
+    # Absolute path to Bazel root (passed via --output_root to Bazel)
+    # Storing bazel cache in tmpfs could be a bad idea because:
+    #  - tmpfs means any files stored here will be stored purely in RAM and will eat into container limits
+    #  - these containers are not persisted from the snapshot
+    #
+    # Bazel will create parent directories (if the user has appropriate permissions), if missing.
+    app.config['BAZEL_ROOT_PATH'] = '/tmp/bazel_changes'
+
     app.config.update(config)
+
     if _read_config:
         if os.environ.get('CHANGES_CONF'):
             # CHANGES_CONF=/etc/changes.conf.py

changes/models/jobplan.py

@@ -1,6 +1,7 @@
 from __future__ import absolute_import
 
 import logging
+import os
 import uuid
 
 from collections import defaultdict
@@ -227,7 +228,7 @@ def get_build_step_for_job(cls, job_id):
                         max_jobs=2 * bazel_cpus), 'type': 'collect_tests'},
                 ],
                 artifacts=['*.xml'],
-                artifact_search_path=current_app.config['BAZEL_TEST_OUTPUT_RELATIVE_PATH'],
+                artifact_search_path=os.path.join(current_app.config['BAZEL_ROOT_PATH'], current_app.config['BAZEL_TEST_OUTPUT_RELATIVE_PATH']),
                 cpus=bazel_cpus,
                 memory=bazel_memory,
             )

changes/utils/bazel_setup.py

@@ -13,7 +13,7 @@
 sudo apt-get -y update || sudo apt-get -y update
 sudo apt-get install -y --force-yes %(bazel_apt_pkgs)s
 
-/usr/bin/bazel --nomaster_blazerc --blazerc=/dev/null --batch version
+/usr/bin/bazel --nomaster_blazerc --blazerc=/dev/null --output_user_root=%(bazel_root)s --batch version
 """.strip()
 
 # We run setup again because changes does not run setup before collecting tests, but we need bazel
@@ -30,7 +30,7 @@
 (sudo apt-get -y update || sudo apt-get -y update) >/dev/null 2>&1
 sudo apt-get install -y --force-yes %(bazel_apt_pkgs)s python >/dev/null 2>&1
 
-(/usr/bin/bazel --nomaster_blazerc --blazerc=/dev/null --batch query \
+(/usr/bin/bazel --nomaster_blazerc --blazerc=/dev/null --output_user_root=%(bazel_root)s --batch query \
     'let t = tests(%(bazel_targets)s) in ($t %(exclusion_subquery)s)' | \
     python -c "%(jsonify_script)s") 2> /dev/null
 """.strip()
@@ -45,6 +45,7 @@ def get_bazel_setup():
     return BASH_BAZEL_SETUP % dict(
         apt_spec=current_app.config['APT_SPEC'],
         bazel_apt_pkgs=' '.join(current_app.config['BAZEL_APT_PKGS']),
+        bazel_root=current_app.config['BAZEL_ROOT_PATH'],
     )
 
 
@@ -90,8 +91,9 @@ def collect_bazel_targets(bazel_targets, bazel_exclude_tags, max_jobs):
         return COLLECT_BAZEL_TARGETS % dict(
             apt_spec=current_app.config['APT_SPEC'],
             bazel_apt_pkgs=' '.join(current_app.config['BAZEL_APT_PKGS']),
+            bazel_root=current_app.config['BAZEL_ROOT_PATH'],
             bazel_targets=' + '.join(bazel_targets),
-            jsonify_script=jsonify_script.read() % dict(max_jobs=max_jobs),
+            jsonify_script=jsonify_script.read() % dict(max_jobs=max_jobs, bazel_root=current_app.config['BAZEL_ROOT_PATH']),
             exclusion_subquery=exclusion_subquery,
         )
 

changes/utils/collect_bazel_targets.py

@@ -4,7 +4,7 @@
 
 targets = sys.stdin.read().splitlines()
 out = {
-    'cmd': '/usr/bin/bazel test --jobs=%(max_jobs)s {test_names}',
+    'cmd': '/usr/bin/bazel --output_user_root=%(bazel_root)s test --jobs=%(max_jobs)s {test_names}',
     'tests': targets,
 }
 json.dump(out, sys.stdout)

tests/changes/buildsteps/test_default.py

@@ -572,7 +572,7 @@ def test_get_allocation_params_with_artifact_search_path(self):
         jobphase = self.create_jobphase(job)
         jobstep = self.create_jobstep(jobphase)
 
-        buildstep = self.get_buildstep(repo_path='source', path='tests', artifact_search_path='out')
+        buildstep = self.get_buildstep(repo_path='source', path='tests', artifact_search_path='/out')
         result = buildstep.get_allocation_params(jobstep)
         assert result == {
             'adapter': 'basic',
@@ -583,7 +583,7 @@ def test_get_allocation_params_with_artifact_search_path(self):
             'pre-launch': 'echo pre',
             'post-launch': 'echo post',
             'artifacts-server': 'http://localhost:1234',
-            'artifact-search-path': 'source/out',
+            'artifact-search-path': '/out',
             'use-external-env': 'false',
             'dist': 'ubuntu',
         }

tests/changes/models/test_job.py

@@ -1,11 +1,9 @@
 from __future__ import absolute_import
 
 import mock
-import os
 
 from flask import current_app
 
-from changes.buildsteps.default import DEFAULT_PATH
 from changes.models.command import CommandType
 from changes.models.jobplan import JobPlan
 from changes.testutils import TestCase
@@ -16,6 +14,7 @@ def _create_job_and_jobplan(self):
         current_app.config['APT_SPEC'] = 'deb http://example.com/debian distribution component1'
         current_app.config['ENCAP_RSYNC_URL'] = 'rsync://example.com/encap/'
         current_app.config['BAZEL_APT_PKGS'] = ['bazel']
+        current_app.config['BAZEL_ROOT_PATH'] = '/bazel/root/path'
 
         project = self.create_project()
         plan = self.create_plan(project)
@@ -59,7 +58,7 @@ def test_autogenerated_commands(self, get_config):
 sudo apt-get -y update || sudo apt-get -y update
 sudo apt-get install -y --force-yes bazel
 
-/usr/bin/bazel --nomaster_blazerc --blazerc=/dev/null --batch version
+/usr/bin/bazel --nomaster_blazerc --blazerc=/dev/null --output_user_root=/bazel/root/path --batch version
 """.strip()
 
         sync_encap_expected = """
@@ -78,15 +77,15 @@ def test_autogenerated_commands(self, get_config):
 (sudo apt-get -y update || sudo apt-get -y update) >/dev/null 2>&1
 sudo apt-get install -y --force-yes bazel python >/dev/null 2>&1
 
-(/usr/bin/bazel --nomaster_blazerc --blazerc=/dev/null --batch query \
+(/usr/bin/bazel --nomaster_blazerc --blazerc=/dev/null --output_user_root=/bazel/root/path --batch query \
     'let t = tests(//aa/bb/cc/... + //aa/abc/...) in ($t )' | \
     python -c "import sys
 import json
 
 
 targets = sys.stdin.read().splitlines()
 out = {
-    'cmd': '/usr/bin/bazel test --jobs=8 {test_names}',
+    'cmd': '/usr/bin/bazel --output_user_root=/bazel/root/path test --jobs=8 {test_names}',
     'tests': targets,
 }
 json.dump(out, sys.stdout)
@@ -104,7 +103,7 @@ def test_autogenerated_commands(self, get_config):
         assert implementation.commands[2].type == CommandType.collect_tests
         assert implementation.commands[2].script == collect_tests_expected
 
-        assert implementation.artifact_search_path == os.path.join(DEFAULT_PATH, current_app.config['BAZEL_TEST_OUTPUT_RELATIVE_PATH'])
+        assert implementation.artifact_search_path == '/bazel/root/path/bazel-testlogs/'
         assert implementation.artifacts == ['*.xml']
 
     @mock.patch('changes.models.project.Project.get_config')
@@ -137,15 +136,15 @@ def test_autogenerated_commands_with_exclusions(self, get_config):
 (sudo apt-get -y update || sudo apt-get -y update) >/dev/null 2>&1
 sudo apt-get install -y --force-yes bazel python >/dev/null 2>&1
 
-(/usr/bin/bazel --nomaster_blazerc --blazerc=/dev/null --batch query \
+(/usr/bin/bazel --nomaster_blazerc --blazerc=/dev/null --output_user_root=/bazel/root/path --batch query \
     'let t = tests(//foo/bar/baz/... + //bar/bax/...) in ($t except (attr("tags", "(\[| )flaky(\]|,)", $t)) except (attr("tags", "(\[| )another_tag(\]|,)", $t)))' | \
     python -c "import sys
 import json
 
 
 targets = sys.stdin.read().splitlines()
 out = {
-    'cmd': '/usr/bin/bazel test --jobs=4 {test_names}',
+    'cmd': '/usr/bin/bazel --output_user_root=/bazel/root/path test --jobs=4 {test_names}',
     'tests': targets,
 }
 json.dump(out, sys.stdout)